I've definitely worked with engineers that are 10x slower or have extremely poor engineering practices: copy-pasting chunks of code, 8+ nested ifs, all code in one giant function, use of global variables throughout, clueless how memory management works/tons of cyclic retains, etc.

I've seen plenty of purported "senior" engineers with 7+ yoe that code worse than new grads.

Now that I'm in FAANG with a high hiring bar, these type of engineers are completely absent. I'm sure that's not a coincidence.